RESUMO
By solid-state reaction and doping, a series of red-emitting phosphors Na(x)Y(0.92-x/3)(MoO(4))(y)(WO(4))(1-y)O(0.5) : zEu(3+) have been synthesized. Through optimization of the process conditions and photoluminescent analysis, one type of red emission is obtained that matches nicely with ultraviolet light-emitting diode (UV-LED) chips.
RESUMO
Ca(x)Sr1-x-1.5y-0.5zMoO4:yEu3+ zNa+ red phosphors were prepared by solid-state reaction using Na+ as charge supply for LEDs (light emitting diodes). The content of charge compensator, Ca2+ concentration, synthesis temperature, reaction time, and Eu3+ concentration were the keys to improving the properties of luminescence and crystal structure of red phosphors. The photoluminescence spectra shows the red phosphors are effectively excited at 616 nm by 311 nm, 395 nm, and 465 nm light. The wavelengths of 395 and 465 nm nicely match the widely applied emission wavelengths of ultraviolet or blue LED chips. Its chromaticity coordinates (CIE) are calculated to be x = 0.65, y = 0.32. Bright red light can be observed by the naked eye from the LED-based Ca0.60Sr0.25MoO4:0.08Eu3+ 0.06Na+.
RESUMO
Under 616 nm monitoring, excitation peaks at 395, 465, and 535 nm were observed for the red-emitting phosphor Li(0.3)Y(0.82)Mo(0.1)W(0.9)O(4+delta): 0.08Eu(3+) (LYMW), which was synthesized using the solid-state method. Particularly in the range of 250 to 420 nm, excited peaks can be assigned to the transitions of O(2-)-->Mo(6+)/W(6+)/Eu(3+) and four sharp peaks can be assigned to the 4f-4f transition of Eu(3+) (approximately 360 nm from the (7)F(0)-->(5)D(4) transition, approximately 380 nm from the (7)F(0)-->(5)L(7) transition, approximately 395 nm from the (7)F(0)-->(5)(L6) transition, and approximately 415 nm from the (7)F(0)-->(5)D(3) transition).